U.S. Pat. No. 7,497,018 B2 discloses a known laser system for creating a linear laser marking. The laser system comprises a radiation source, a collimating lens with an optical axis and a conical mirror with a cone axis as well as a deflecting mirror, which is arranged between the collimating lens and the conical mirror. A collimating lens is a special focusing lens assembly with infinite focal length. A conical mirror is a reflecting optical element that is shaped at least partially in the form of a cone with a base surface and a lateral surface adjacent to the base surface, whereby the lateral surface is configured as a reflecting surface from which a laser beam is deflected and expanded.
The radiation source is configured as a laser diode that emits a laser beam along a direction of propagation, whereby the direction of propagation of the laser beam runs parallel to the optical axis of the collimating lens. The laser beam strikes the collimating lens, which then creates a collimated laser beam out of the divergent laser beam. The collimated laser beam strikes the deflecting mirror, which deflects the collimated laser beam by 90° in the direction of the conical mirror. The conical mirror deflects the collimated laser beam and creates a laser beam that propagates in a plane perpendicular to the collimated laser beam, and then the conical mirror creates a linear laser marking on a projection surface, for example, a wall, a ceiling and/or a floor. A linear laser marking having a beamwidth of 180° is created when the collimated laser beam illuminates half of a cone. As long as the radius of the collimated laser beam is greater than the distance between the cone tip and the center of the collimated laser beam, a closed laser marking encompassing 360° is created, whereby the intensity of the linear laser marking and thus the visibility increase in the section of the cone where the center of the collimated laser beam is located. The cone axis of the conical mirror is arranged so as to be offset parallel to the optical axis of the collimating lens. Due to the parallel offset of the cone axis, the center of the collimated laser beam does not strike the cone tip but rather, the lateral surface of the conical mirror.